The present invention relates generally to biomedical electrodes.
Biomedical electrodes are useful for both stimulation and body monitoring functions. Stimulation uses of biomedical electrodes include transcutaneous electronic nerve stimulation (TENS) for the treatment of pain and neuromuscular stimulation (NMS) as, for example, treatment for scoliosis. Body monitoring uses for biomedical electrodes include electrocardiogram (ECG) for monitoring heart activity.
Among biomedical electrodes in existence are those of Phipps et al, Cartmell and Larimore. Phipps et al in U.S. Pat. No. 3,170,459 discloses a biomedical instrumentation electrode constructed from multiple plies of discs made from a relatively inflexible material, i.e., cork. The electrode utilizes a conductive gel to establish contact with the body. Cartmell in U.S. Pat. No. 4,543,958 discloses a medical electrode assembly. The electrode has a flexible, dimensionally stable substrate which is striped with an electrically conductive paint. The electrode is then clamped into a bulky cable connector. Larimore in U.S. Pat. No. 4,458,696 (assigned to Minnesota Mining and Manufacturing Company) discloses a TENS electrode with a raised structure to permit entry of an attachment to a tubular electrical conductor.
These electrodes suffer from several deficiencies including that all are "high profile" electrodes and that the electrodes do not "conform" well to the body.
For monitoring electrodes electrical currents passing through the electrodes are relatively low so that excellent electrical conductivity in the electrode is required for proper performance, i.e., the ability of the biomedical electrode to pick up and transmit electrical signals obtained from the body. In most instances, good electrical performance requires that silver be utilized as a conductive element in the electrode in order to promote the proper conductivity, however, silver is an extremely expensive ingredient, the use of silver in disposable biomedical electrodes makes monitoring body functions a costly endeavor.